Search for the Higgs boson in the H → ZZ → 2l2ν channel in 1.6 fb−1

This is a condensed description with plots for the analysis CMS-HIG-11-016.

Abstract

A search for the Higgs boson in pp collisions at the LHC at a center-of-mass energy of 7 TeV is presented. The results are based on a data sample corresponding to an integrated luminosity of 1.6 fb−1 recorded by the CMS experiment. The search is conducted in the decay channel H → ZZ → 2l2ν. No excess is observed in the transverse mass distributions. Limits are set on the production of the Higgs boson in the context of the Standard Model and in the presence of a sequential fourth family of fermions with high masses.

Main Results

We find no evidence of Standard Model Higgs boson production. We measure the 95% mean expected and observed C.L. upper limits on the cross section σ BR( H → ZZ → 2l 2ν) for masses in the range 250 − 600 GeV/c2 . Results are obtained using a CLs approach with a flat prior for the cross section, for 1.6 fb−1 . We also measure the ratio R of the 95% C.L. cross section upper limit σ to the SM cross section, σSM as a function of the Higgs mass mH. With 1.6 fb−1 , the Standard Model Higgs with masses in the range 340 − 375 GeV/c2 can be excluded at 95% CL.

Results for the SM augmented with a 4th generation of particles are shown as well. This is the model in which the presence of another fermion family produces an enhancement of the dominant gluon-gluon fusion cross section. A scenario with fourth generation quark and lepton masses of 600 GeV/c2 is considered. With 1.6 fb−1 , Higgs masses in the range 250 − 550 GeV/c2 can be excluded at 95% CL.

Physics Analysis Summary

A note summarizing the analysis and the results can be found here: PAS

Figures

All public plots and tables from this analysis are collected here. Click on a figure to enlarge it, then double click to go to normal size again.
FIGURE FILES Description
met_el.png png, gif, pdf Missing transverse energy distribution in the electron channel at pre-selection level for 1.6 fb−1 of data.
met_mu.png png, gif, pdf Missing transverse energy distribution in the muon channel at pre-selection level for 1.6 fb−1 of data.
dphi_el.png png, gif, pdf DeltaPhi(MET,nearest jet) after pre-selection + MET cut in the electron channel for 1.6 fb−1 of data.
dphi_mu.png png, gif, pdf DeltaPhi(MET,nearest jet) after pre-selection + MET cut in the muon channel for 1.6 fb−1 of data.
mt250_el.png png, gif, pdf Transverse mass of the LLNuNu system for the mH=250 GeV/c2 selection in the electron channel after all cuts except the MT-window cut, 1.6 fb−1 of data.
mt350_el.png png, gif, pdf Transverse mass of the LLNuNu system for the mH=350 GeV/c2 selection in the electron channel after all cuts except the MT-window cut, 1.6 fb−1 of data.
mt250_mu.png png, gif, pdf Transverse mass of the LLNuNu system for the mH=250 GeV/c2 selection in the muon channel after all cuts except the MT-window cut, 1.6 fb−1 of data.
mt350_mu.png png, gif, pdf Transverse mass of the LLNuNu system for the mH=350 GeV/c2 selection in the muon channel after all cuts except the MT-window cut, 1.6 fb−1 of data.
systematics-summary-table.png png, gif, pdf Summary table of all systematic uncertainties on the final event yields in percent.
final-yields-table-LP.png png, gif, pdf Summary table of the final yields for expected background and signal events, as well as observed events in 1.6/fb of data.
limits_LP_2.png png, gif, pdf 95% CL limit of the ratio of expected/measured cross section x BR over Standard Model for 1.6/fb of data.
limits_LP_4th_2.png png, gif, pdf 95% CL limit of the ratio of expected/measured cross section x BR over Standard Model+4th generation extension for 1.6/fb of data.
xs_LP_2.png png, gif, pdf Upper limit of the expected/measured cross section x BR for 1.6/fb of data.
xs_4th_LP_2.png png, gif, pdf Upper limit of the expected/measured cross section x BR assuming a 4th generation extension of the Standard Model, for 1.6/fb of data.
event_163659_21497971_3D_white.png png, gif, pdf Event display of the highest transverse mass event in the muon channel analysis of 1.6/fb.
event_163659_21497971_rho_phi_white.png png, gif, pdf Event display of the highest transverse mass event in the muon channel analysis of 1.6/fb.
event_163659_21497971_rho_z_white.png png, gif, pdf Event display of the highest transverse mass event in the muon channel analysis of 1.6/fb.

-- PetraMerkel - 19-Aug-2011

Topic attachments
I Attachment History Action Size Date Who Comment
GIFgif dphi_el.gif r1 manage 12.0 K 2011-08-19 - 11:44 PetraMerkel  
PDFpdf dphi_el.pdf r1 manage 23.0 K 2011-08-19 - 11:44 PetraMerkel  
PNGpng dphi_el.png r1 manage 14.7 K 2011-08-19 - 10:59 PetraMerkel  
GIFgif dphi_mu.gif r1 manage 12.0 K 2011-08-19 - 11:44 PetraMerkel  
PDFpdf dphi_mu.pdf r1 manage 22.9 K 2011-08-19 - 11:44 PetraMerkel  
PNGpng dphi_mu.png r1 manage 14.8 K 2011-08-19 - 10:59 PetraMerkel  
GIFgif event_163659_21497971_3D_white.gif r1 manage 421.4 K 2011-08-19 - 11:50 PetraMerkel  
PDFpdf event_163659_21497971_3D_white.pdf r1 manage 516.7 K 2011-08-19 - 11:51 PetraMerkel  
PNGpng event_163659_21497971_3D_white.png r1 manage 702.6 K 2011-08-19 - 11:50 PetraMerkel  
GIFgif event_163659_21497971_rho_phi_white.gif r1 manage 339.6 K 2011-08-19 - 11:51 PetraMerkel  
PDFpdf event_163659_21497971_rho_phi_white.pdf r1 manage 359.0 K 2011-08-19 - 11:51 PetraMerkel  
PNGpng event_163659_21497971_rho_phi_white.png r1 manage 410.2 K 2011-08-19 - 11:50 PetraMerkel  
GIFgif event_163659_21497971_rho_z_white.gif r1 manage 191.1 K 2011-08-19 - 11:51 PetraMerkel  
PDFpdf event_163659_21497971_rho_z_white.pdf r1 manage 294.5 K 2011-08-19 - 11:51 PetraMerkel  
PNGpng event_163659_21497971_rho_z_white.png r1 manage 317.6 K 2011-08-19 - 11:50 PetraMerkel  
GIFgif final-yields-table-LP.gif r1 manage 76.4 K 2011-08-19 - 11:31 PetraMerkel  
PDFpdf final-yields-table-LP.pdf r1 manage 72.8 K 2011-08-19 - 11:32 PetraMerkel  
PNGpng final-yields-table-LP.png r1 manage 94.6 K 2011-08-19 - 11:13 PetraMerkel  
GIFgif limits_LP_2.gif r1 manage 14.6 K 2011-08-19 - 11:42 PetraMerkel  
PDFpdf limits_LP_2.pdf r1 manage 25.8 K 2011-08-19 - 11:42 PetraMerkel  
PNGpng limits_LP_2.png r1 manage 21.2 K 2011-08-19 - 11:14 PetraMerkel  
GIFgif limits_LP_4th_2.gif r1 manage 14.5 K 2011-08-19 - 11:43 PetraMerkel  
PDFpdf limits_LP_4th_2.pdf r1 manage 25.7 K 2011-08-19 - 11:43 PetraMerkel  
PNGpng limits_LP_4th_2.png r1 manage 21.1 K 2011-08-19 - 11:14 PetraMerkel  
GIFgif met_el.gif r1 manage 14.0 K 2011-08-19 - 11:43 PetraMerkel  
PDFpdf met_el.pdf r1 manage 24.9 K 2011-08-19 - 11:43 PetraMerkel  
PNGpng met_el.png r1 manage 16.2 K 2011-08-19 - 10:57 PetraMerkel  
GIFgif met_mu.gif r1 manage 14.9 K 2011-08-19 - 11:43 PetraMerkel  
PDFpdf met_mu.pdf r1 manage 25.6 K 2011-08-19 - 11:43 PetraMerkel  
PNGpng met_mu.png r1 manage 16.7 K 2011-08-19 - 10:58 PetraMerkel  
GIFgif mt250_el.gif r1 manage 13.1 K 2011-08-19 - 11:39 PetraMerkel  
PDFpdf mt250_el.pdf r1 manage 23.3 K 2011-08-19 - 11:40 PetraMerkel  
PNGpng mt250_el.png r1 manage 16.6 K 2011-08-19 - 11:00 PetraMerkel  
GIFgif mt250_mu.gif r1 manage 13.8 K 2011-08-19 - 11:41 PetraMerkel  
PDFpdf mt250_mu.pdf r1 manage 24.5 K 2011-08-19 - 11:41 PetraMerkel  
PNGpng mt250_mu.png r1 manage 17.9 K 2011-08-19 - 11:01 PetraMerkel  
GIFgif mt350_el.gif r1 manage 13.3 K 2011-08-19 - 11:40 PetraMerkel  
PDFpdf mt350_el.pdf r1 manage 23.8 K 2011-08-19 - 11:40 PetraMerkel  
PNGpng mt350_el.png r1 manage 16.5 K 2011-08-19 - 11:01 PetraMerkel  
GIFgif mt350_mu.gif r1 manage 14.5 K 2011-08-19 - 11:41 PetraMerkel  
PDFpdf mt350_mu.pdf r1 manage 24.9 K 2011-08-19 - 11:41 PetraMerkel  
PNGpng mt350_mu.png r1 manage 16.9 K 2011-08-19 - 11:01 PetraMerkel  
GIFgif systematics-summary-table.gif r1 manage 45.8 K 2011-08-19 - 11:32 PetraMerkel  
PDFpdf systematics-summary-table.pdf r1 manage 63.5 K 2011-08-19 - 11:32 PetraMerkel  
PNGpng systematics-summary-table.png r1 manage 82.7 K 2011-08-19 - 11:13 PetraMerkel  
GIFgif xs_4th_LP_2.gif r1 manage 19.2 K 2011-08-19 - 11:42 PetraMerkel  
PDFpdf xs_4th_LP_2.pdf r1 manage 31.8 K 2011-08-19 - 11:42 PetraMerkel  
PNGpng xs_4th_LP_2.png r1 manage 27.3 K 2011-08-19 - 11:15 PetraMerkel  
GIFgif xs_LP_2.gif r1 manage 19.3 K 2011-08-19 - 11:42 PetraMerkel  
PDFpdf xs_LP_2.pdf r1 manage 31.0 K 2011-08-19 - 11:42 PetraMerkel  
PNGpng xs_LP_2.png r1 manage 26.8 K 2011-08-19 - 11:15 PetraMerkel  
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